Need for a consensus on the methods by which to measure joint mobility and the definition of norms for hypermobility that reflect age, gender and ethnic-dependent variation: is revision of criteria for joint hypermobility syndrome and Ehlers-Danlos syndrome hypermobility type indicated?

Sir, Joint mobility is a continuous trait that varies with joint location and is strongly influenced by age, gender and ethnic origin. Variation in joint mobility probably begins in utero and can be expressed, often most dramatically, in individuals with heritable syndromes, such as forms of Ehlers–Danlos syndrome (EDS) and various conditions in which joint contracture is a conspicuous feature. In individuals with these disorders, the diagnosis generally depends on the sum of the different features of the condition, in a sense the gestalt of the presentation. In general, the ability to formulate these diagnoses depends in large part on the experience of the clinician and awareness of the classical descriptions of the syndromes. Individuals with syndromic forms of abnormalities in joint mobility tend to fall into the diagnostic realm of the geneticist, paediatrician, rheumatologist or other specialists, depending on the national preferences for referral. Their clinical care is often assumed by rheumatologists and physical therapists. A second and much larger group of individuals occupies the attention of both rheumatologists and geneticists—those who have joint mobility that seems out of the usual range (usually increased) at some point in their lives. They may have acute or chronic subluxation, may have joint-related pain that seems out of proportion to clinical signs and more often than not are female. In part, because of the dissociation of signs and symptoms, this group of individuals with joint hypermobility, tendency to subluxation and joint pain has proved frustrating to clinicians and to the affected individuals themselves and has led to alienation from the medical system and increased demands for recognition and the creation of meaningful, shared and useful formats for diagnosis and treatment.